1. Field of the Invention
The present invention relates to a clean bench for maintaining a clean atmosphere in a partitioned space.
2. Description of the Related Art
For example, in a clean room for manufacturing semiconductors, a high level of cleanliness is maintained by supplying air containing a very small amount of dust through a vent, the air being purified by an air purifier having a high efficiency particulate air (HEPA) filter. Construction of such a clean room involves extensive work including designing and installing filtering units and ducts in the entire building and each segment of a partitioned floor.
A clean bench, which is installed in a normal room environment and used, is known as an example of means for easily maintaining a clean atmosphere in a confined space without requiring extensive construction work. Such a clean bench measuring, for example, about 1 m wide by 2 m high has a clean unit including a dust-removing filter and supplies filtered air into a clean area of the clean bench to maintain cleanliness only in the clean area (see, for example, Japanese Unexamined Patent Application Publication No. 2001-141273).
However, cleanliness in the clean area of the clean bench described above cannot reach a satisfactory level unless the clean bench is installed in an environment with a certain level of cleanliness. For example, when a known clean bench is installed and used in a misty environment, such as a manufacturing site, a predetermined cleanliness level of a clean area is not necessarily reached.